NJ.com member kingofspain reminds us that Burnett has been through rough patches before:

"A lot of people seem to forget that Burnett has always been
inconsistent. The fact that his paycheck is bigger than it was in the
past isn't going to change that. I don't think you can say he isn't
right for NY when he pitched so well last year.

He's never been as bad as this year but maybe he's got a slight
injury or he's just having a bad year. Those happen to pitchers (and
position players) everywhere, not just in NY.

Also, the fact that he's overpaid isn't his fault, it's the Yankees'
fault. He was never worth $16.5m a year but if someone offers him a
contract of that size, what's he supposed to do?"